Process of fermentation for use in manufacture of yeast and spirit.



UNITED sTATEs PATENT oEEioE.

DESIDER FOR/STER AND PHILIPP FINITZER, OF BUDAPEST, AUSTRIA-HUNGARY.

PROCESS OF FERMENTATION FOR USE IN MANUFACTURE OF YEAS'T AND SEIRIT.

No Drawing.

To all whom it may concern:

Be it known that we, DEsiDER FoRsTER and Pi-iiLiPr FINITZER, subjects of the Kingdom of I-Iungary, and residents of Budapest, Austria-Hungary, have invented certain new and useful Improvements in the Process of Fermentation for Use in the Manufacture of Yeast and Spirit, of which the following is a clear, full, and exact description.

The present invention relates to processes of fermentation and particularly to that part of the processes involving the propagation of the saccharomyces or yeast fungi, the objects of the invention being to eliminate as far as practicable all element of chance or uncertainty and to secure better and more uniform results followed by ahigher yield of alcohol than by processes heretofore practiced.

The .invention consists, generally stated, in .internuptingitbafermentaimnOI eation oftheyeastunash due to thepr e sence ofwlacticacid bacteria by the addition of sufficient inorganic acid suohas sulfuric acid while the l act ic acid fermentation is in active progress, but before the acidiication has progressed to an extent which will materially interfere with the vigor of the lactic acid bacteria. The quantity of inorganic acid added is sufficient to sub'- stantially stgp. the lactic 'acid-fermentation withontwdestroying t ie vitality or vigor of thelactic acid bacteria, the latter thus remaining in the mash in a vigorous condition.

It has heretofore been generally recognized that yeast prospers best in slight-ly acid solutions b-ecause the presence of acids is detrimental to the growth or development of inimical micro-organisms, thus, in prior processes protection of the yeast mash has been sought in the use of lactic acid originated through spontaneous fermentation. In other processes various means for securing antiseptic conditions were employed, or

the yeast mash soured by spontaneous lactic acid fermentation was boiled or heated to higher temperatures to kill inimical bacteria before the yeast mash Was mixed with the startin yeast or sulfuric acid was added as a substitute for the lactic acid process.

It has been ascertained by the inventors that the fermentation proceeds much more advantageously and more alcohol is obtained Specification of Letters Patent.

Application led June 9, 1909.' Serial No. 500,996.

- about 5% Patented Dec. 13, 1910.

from the same quantity of sugar if at thc, time of theyeastfermentation lactic acid bacteriav are present, because the yeast is protected against the invasion or multiplication of inimical bacteria by the presence of vigorouslactic acid bacteria and yeastfernientation is promoted by the symbiosis of said vigorous lactic acid bacteria and the saccharomyces. It is to be noted, however, that lactic acid in excessv produced by lactic acid bacteria .is just as harmful as is the product of alcoholic fermentation; the alcohol, as proven by scientific research at first stops the growth of the saccharomyces, then reduces its fermentative power 70 and finally stops the fermentation altogether. This is also true with respect to the lactic acid bacteria which are weakened by the presence of an excess of lacticacid and in the process as heretofore practiced with lactic acid fermentation this excess invariably occurred. Such prior processes pushed the acidification to a degree where 20 cubic centimeters of the yeast mash filtrate required Q-QA cubic centimeters of normal 80"' caustic soda or more, for neutralization.

In the present invention when the acidity of the yeast mash has reached a certain def 'i grec and while the lactic acid bacteria are in full vigor suflicient sulfuric acid or simil larly acting inorganic acid is added to interrupt the lactic acid fermentation wit-hout killing or otherwise 'materially impairing the vigor of the milk acid bacteria. l, A practical example of tho process `di'wt'he present invention is as follows: In startingl the process of manufacture the yeast mash is pparec o; a mixture of equal quantities 0 aai naar@ .site bruisec iiialt exanfiple lflielquayiif this mixture being about 5% dry measure dfA the original substance of the mash. The mixture is diluted to such degree that ifl heated as usual to 66-690 centigrade it.l should have, after two hours of inversrivon, s .,l.. of 19-20O a ing i sac-A 'charimeten While this process of preparation of the yeast mash may be followed throughout the entire course of manufacture, a preferred and somewhat simplified process is to prepare the yeast mash from the main mash, as, for instance, by taking of the main mash and adding to it when in the yeast butt, so much ground malt that the yeast mash so prepared will 110 cr starting yeast is adde l Y Q;

or multiplication of iiiimical 0bacteri sliOWWQQuLMLQX-QQ (Balling) sacchari meter uditi-' heating up to (S6-68 centigrade and after about two hours of inversion.

After the yeast mash is prepared as above, milk acid fermentation is per'mitted or is caused to take place as usual at 50-62-0 centigrade and While the fermentation is still of undiminished act-ivit furggmapicigsggdded in sufficient quantity to interrupt the lactic acid fermentation Without destroying or inaterially reducing the vitality of the milk acid bacteria. The prepared yeast mash is then cooled down to about 10-20O centi-- grade, (the desirable temperature for the main fermentation), and

di The yeast mash is no-W fermentedto l? saccharimeter (Balling) and after faking cut 10% for subsequent use the remainder is added to the cooled main mash for fermentation purposes.

The time when the lactic acid i''ernicnta tion is to be interrupted by the addition of sulfuric or equivalent inorganic acid is indicated by the acid content and is preferably as soon as E20 cubic centimeters of the yeast mash filtrate require 0.8-1.3 cubic centimeters normal caustic soda for neutralization. These percentages may, Linder some conditions, be varied, but best results have so far been secured between the limits mentioned.

The sulfuric acid of 660 Baume to be added is preferably in the proportion of about onehundred cubic centimeters to each V one hundred liters of yeast mash of about 20o saccharimeter (Balling).

As hereinbefore indicated, the addition of the sulfuric acid While it interrupts the progress of the lactic acid fermentation does not destroy the lacticacidhha .the latter retaining their full Vitality nd vigor to f t1 Y fropt and secondary fermentation resulting therefrom. The percentage of sulfuric acid added may be varied to some extent, depending upon the ravv material used for the manufacture of the yeast mash. The amount added in the present process is not sufficient to be dangerous to the yeast and its addition requires no particular precautions, its primary function being to control or prepare the lactic acid bacteria for the performance of their functions in the subsequent fermentation, although it may also serve to supply acid required fer the process of fermentation in the mash. In the process of the present invention the percentage of acidity may be less than in ordinary practice, owing to the protection afforded by the lactic acid bacteria which are present in the mash ina vigorous condition.

bacteria is employed which consists in interrupting the spontaneous acidification of the yeast mash due to the lactic acid bacteria by adding inorganic acid sufficient only` in quantity to arrest the multiplication of lactic acid bacteria Without destroying the Vitality of the said bacteria then present in the mash, fermenting the mash With yeast and in adding said yeast mash to the main mash for fermentation.

2. The improvement in the process of alcoholic fermentation which consists in the preparation of a yeast mash by the fermentation due to lactic acid bacteria, said fermentation being interrupted When in a highly active stage and before the addition of the yeast, by adding inorganic acid in quantity insufficient to destroy the vitality of the lactic acid bacteria, fermenting the mash with yeast and in adding the prepared yeast mash to the main mash.

3. The improvement in the process of fermentation of Saccharomyces and lactic acid bacteria which consists in interrupting the fermentation due to the presence of lactic acid bacteria when the acidity issuch that approximately 20 cubic centimeters of the yeast mash filtrate require 0.8-1.3 cubic centimeters of normal caustic soda. for neutralizaticn, by the addition of an inorganic acid, and in subsequently fermenting the mash With yeast and adding said yeast mash to the main mash.

4. The improvement in the process of fermentation Which consists in preparing a mash, acidifyiiig said mash by lactic acid fermentation until a certain degree of lactic acidity has been reached, then interrupting the lactic acid fermentation Without destroying the lactic acid bacteria by the addi -tion of an inorganic acid and subsequently subjecting the mash containing the lactic acid bacteria tpmyeasatnfyerjgientation, and adding the yeast mash to the main mash.

DESIDER FORSTER. PHILIPP FINITZER. Witnesses:

LAJo GYULA, TYsrAN JANos. 

